Patek Philippe Nautilus 5712 (5712/1A-001)

Patek Philippe's new Ref. 5200 Gondolo 8 Days, Day & Date Indication appeals to all aficionados who prefer manually wound timepieces. For this model, the Genevan workshops developed a new caliber that in many respects is reminiscent of the Ref. 5100 "10-Day", presented 13 years ago to welcome the new millennium. Unlike the 5100, however, the new Gondolo contains innovative Silinvar® components.
A role model of energy efficiency
The rectangular caliber 28-20 REC 8J PS IRM C J form movement enriches the Patek Philippe collection of currently produced manually wound movements. It was developed explicitly for the Ref. 5200 Gondolo; in twin in-line barrels, it stores the power needed to guarantee that it will run non-stop for 192 hours. This doesn't mean that the watch will stand still then; instead, it has the power reserve required to safeguard the steady amplitude of the balance and its rate accuracy up to and including the eighth day. Insiders will no doubt remember the Patek Philippe "10-Day" which had its debut in the year 2000 and delivered power for two additional days. The fact that the Ref. 5200 falls short by two days is associated with the date indication and the day aperture; advancing these calendar displays every day at midnight requires a lot of energy. This is remarkable especially because the calendar is an instantaneously switching mechanism in which the day and the date switch forward simultaneously at midnight, within three milliseconds - faster than the blink of an eye. In the process, the large disk of the prominent day-of-week display has to be advanced by one increment as well. Indeed, a power reserve of this magnitude is quite remarkable, given the eight lightning-fast calendar switching cycles. This applies all the more because when quantifying power reserve, Patek Philippe always factors in the energy needed for one further calendar switching cycle - for functional reliability reasons.

To a great extent, the staying power of the new caliber 28-20 REC 8J PS IRM C J is due to the patented oscillator with a Spiromax® balance spring and a Pulsomax® escapement, for which Patek Philippe has leveraged all the benefits of the innovative silicon-based Silinvar® material. It is the manufacture's first 4-hertz movement with these patented elements. The Pulsomax® escapement with a Silinvar lever and escape wheel requires no lubrication and yet is practically friction-free, which saves energy each time the lever contacts the escape wheel. With 5.53 million contacts in eight days, this degree of efficiency really comes to the fore in a 4-hertz movement (28,800 vph). Additionally, the extremely hard, totally antimagnetic and corrosion-resistant Silinvar® material is two-thirds lighter than steel, which further optimizes the energy balance. The efficiency of the escapement and the rate accuracy of the watch are further enhanced by precise machining to thousandths of a millimeter as well as the patented geometry of the Silinvar® lever and escape wheel developed by Patek Philippe. The patented Spiromax® balance spring is made of the same revolutionary material. Thanks to the precisely computed geometry of the Patek Philippe terminal curve, thinness is combined with totally symmetric expansion and contraction to optimize isochronism. The advantages of Silinvar® have a favorable impact on uniform breathing, which makes a decisive contribution to high rate accuracy. This innovative escapement can be admired through the sapphire-crystal case back; depending on the angle of the incident light, the balance spring, the lever, and the escape wheel can be recognized by their purple-to-bluish hue. The aesthetic appeal is obviously inspired by the "10-Day" caliber and apart from the large mainspring barrel plate, the caliber features a clever "trompe l'oeil" going train bridge, which at first sight seems to be an ensemble of three separate, gracefully curved bridges, as well as a generously dimensioned and thus highly rigid balance cock that securely carries the readily visible oscillator. The surfaces are decorated with Geneva striping and gold-filled engravings, the edges chamfered and polished, and the flanks longitudinally grained. This is a true gem that deserves to be showcased in its display window. Despite the addition of an elaborate instantaneous calendar mechanism with a date hand and an aperture day, the new caliber 28-20 REC 8J PS IRM C J is merely 5.05 mm high, just like the movement of the Ref. 5100 "10-Day"..
Timeless Art Deco beauty
The innovative rectangular long-distance runner is housed in an anatomically curved and elongated white-gold case with two-tiered flanks reminiscent of the most memorable Art Deco creations. In the Geneva workshops, it is crafted from solid gold bars using the cold-forming technology, shaped to perfection in numerous consecutive steps, and then gradually polished to a mirror finish by experienced specialists who invest countless hours to achieve the perfect result. The screwed case back incorporates an anatomically contoured sapphire-crystal insert, and the crystal that protects the dial is ground to a convex shape that follows the silhouette of the case without distorting the view of the elegant and well-organized face. The dial is available in blue sunburst or silvery white. Emphasizing the ninth day in red to remind the owner to wind the mainspring, the 8-day power-reserve indicator occupies the upper half of the dial. Its lower half is reserved for the calendar functions, featuring a 31- day scale for the date and an aperture for the day of the week. The seconds subdial is integrated in the date circle. Securely riveted to the face, the faceted white-gold hour markers are mirror-polished for the blue dial and blackened for the silvery opaline dial. The faceted Dauphine-style hour and minute hands in white gold are either mirror-polished or matt-blackened to match the dial color. The date hand with the red tip and the hands for the subsidiary seconds and power-reserve indicator are finished in white lacquer to contrast against the blue dial and blackened to match the silvery white dial.

The new Patek Philippe Ref. 5200 Gondolo 8 Days, Day & Date Indication is worn on a hand-stitched alligator strap with large square scales, which is secured with an 18K white-gold prong buckle. The strap is shiny blue to match the blue dial and matt black for the model with the silvery white dial.